Jet propulsion engines



April 27, 1965 F. c. MARCHANT JET PROPULSION ENGINES 3 Sheets-Sheet 1 Filed 001;. 16, 1961 April 27, 1965 F. c. l. MARCHANT JET PROPULSION ENGINES 3 Sheets-Sheet 2 Filed Oct. 16. 1961 Apri! 27, 1965 F. c. 1. MARCHANT 3,180,087

JET PROPULSION ENGINES Filed Oct. 16. 1961 3 Sheets-Sheet 3 United States Patent 3,180,087 EET PROPULSEON ENGlNES Francis Charles Ivor Marchant, Bristol, England, assignor to Bristol Siddeley Engines Limited, Bristol, England, a British company Filed Oct. 16, 1961, Ser. No. 145,156 Claims priority, application Great Eritain, Get. 21, 1969, 35,261/60 Claims. (Cl. 6ll35.55)

This invention relates to jet propulsion engines.

According to this invention there is provided a gasturbine engine comprising a turbine system, a compressor system driven by the turbine system, a jet pipe connected to receive exhaust gases from the turbine system, an annular air duct surrounding the jet pipe and connected to receive compressed air from the compressor system, and a propulsion nozzle which is connected to receive exhaust gas from the jet pipe and air from the air duct and which is rotatable relative to the engine, rotation of the nozzle serving to adjust the direction of its discharge of the gas and air.

In preferred arrangements the gas-turbine engine is of the by-pass or ducted fan type having a by-pass duct communicating at its upstream end with the deliveryof a compressor or ducted fan of the compressor system and the annular air duct is connected to the downstream end of the by-pass duct. In one construction the propulsion nozzle has coaxial inner and outer walls defining an inner passage and an annular outer passage, the inner passage receiving the gas and the annular outer passage receiving the compressed air.

Preferably the wall of the jet pipe is surrounded by an outer wall coaxial therewith, the inner and outer boundaries of the annular duct being defined by the two walls.

According to a feature of the invention the nozzle is carried by a bearing mounted on the said outer wall. The bearing is preferably disposed externally of the annular duct.

The jet pipe and the surrounding annular air duct may be of elbow-pipe form.

in preferred constructions the nozzle is of generally elbow-pipe form and is rotatable about the lengthwise axis of its inlet end portion to adjust the direction of its discharge of the gas and air.

According to a feature of the invention the axis of rotation of the nozzle extends obliquely to the lengthwise axis of the engine.

Two embodiments of the invention will now be described by way of example with reference to the accompanying diagrammatic drawings in which- FIGURE 1 is a side elevation of a gas turbine jet propulsion engine of the ducted fan type,

FIGURE 2 is a plan of the exhaust section of the engine shown in FIGURE 1,

FIGURE 3 is a sectional view on a larger scale of part of the bearing for the propulsion nozzle,

FIGURE 4 shows a side elevation of a second embodiment,

FIGURE 5 shows an end elevation as seen in the direction of the arrow W of FIGURE 4, and

FIGURE 6 shows a jet pipe and nozzle section as seen in the direction of the arrow X in FIGURE 5.

The gas turbine jet propulsion engine shown in FIG- URE 1 is of the ducted fan type in which the air intake leads to a low pressure axial flow compressor A having a divided delivery. Part of the compressed air therefrom passes in succession through a high pressure axial flow compressor B, a combustor C and a two stage turbine D. The first stage turbine is coupled to drive the compressor B and the second stage turbine is coupled to drive the ice compressor A, the rotary system formed by first stage turbine and compressor B, and that formed by the second stage turbine and compressor A being free to rotate relative to each other. The remainder of the air from the compressor A is conveyed through an annular by-pass duct 11 which surrounds the engine and through the exhaust gas jet pipe 12.

Referring to FIGURE 1 and 2, the jet pipe 12 bends laterally away from the engine axis and leads to a single rotatable propulsion nozzle 13 which is of elbow-pipe shape and is offset from the lengthwise axis of the engine. The nozzlel3 has inner and outer walls 14, 15 and is formed with an outlet the plane of which extends obliquely to the direction of flow of the gases emerging from the nozzle. The part of the annular by-pass duct 11 which surrounds the jet pipe is defined by the jet pipe wall and an outer wall 16, and follows the bend of the jet pipe. The out-er wall 15 of the nozzle is secured to the outer wall 16 of the duct through a bearing assembly as described below, the arrangement being such that the outer wall 15 of the nozzle forms an extension of the outer wall 16 of the duct and the nozzle inner wall 14 forms an extension of the jet pipe'wall. A small working clearance is provided between the downstream end of the jet pipe and the upstream end of the inner wall of the nozzle.

The jet pipe and surrounding annular duct deflect the gases through an angle which is less than and the axis of rotation of the nozzle is therefore inclined slightly rearwardly.

As seen in FTGURE 2, the nozzle 13 is provided adjacent its outletwith a row of upright guide vanes 17 which are shaped to deflect the gas fiow through approm'mately ninety-ave degrees so that it may be discharged from the V nozzle 13 in a rearward direction substantially parallel to the engine ams to obtain forward thrust. The inner wall of the nozzle terminates at and is secured to the nose portions of the vanes 17. The guide vanes 17 at the ends of the row co-operate with the curvature of the outer wall of the nozzle to deflect the air flow in like manner so that the propulsive jet from the nozzle consists of a core of engine hot exhaust gas and a surrounding annular flow of relatively cold by-pass air.

The outer wall 16 of the annular duct is bolted at its upstream end to the downstream end of the engine casing 10 and the jet pipe is supported from the outer wall 16 of the duct by eight equally spaced radial vanes 18 which extend along substantially the full length of the jet pipe. The inner wall 14 of the nozzle is supported from the outer wall 15 by means of five vanes 19, two of which extend below the lower part of the inner wall, two more of which extend above the upper part of the inner wall in vertical alignment with those vanes beneath them, and the remaining one of which extends laterally opposite the inside of the bend in the nozzle.

Referring to FIGURE 3, the nozzle 13 is rotatably mounted by means of an intermediate bearing assembly on both the outer wall 16 of the duct and a further supporting structure 2t} which may for example be part of a nacelle wall for the engine or part of an'aircraft fuselage.

The bearing assembly includes two annular members 21 and 24, of which member 21 provides the downstream end part of the outer wall 1d of the annular duct, and of which member 24 forms the upstream end part of the outer wall 15 of the nozzle. Member 21 is flanged at 22 for bolting to a similar flange 23 on the adjacent upstream portion of wall 16, and member 24 is flanged at its downstream end at 25 for bolting to a flange 26 on the adjacent part of wall 15 of the nozzle. The upstream end portion of the member 24 extends axially but is offset outwards of the outer Wall 16. On its outer periphery this offset portion of the member 24 is formed with a ti-section groove providing the inner race for Patented Apr. 27, 1955 a row of ball'bearings 323,

3 and this groove is flanked by grooves containing sealing rings 33. The outer race of the bearing is formed in two parts one of which is provided by an L-shaped ring 27 and the other by a ring 31 which is integral with the member 21 and which is flanged at Flange 25% of ring 31, and the adjacent flange of ring 27 are bolted to the stern of a T-section ring 29 which is secured to the supporting structure it The bearing attorded by balls 32 and the V-section grooves, which form a square section channel, acts both as a journal and as a thrust hearing. The offset portion of member 24 is protected on itsinner side by a para el part of the member 21, but small clearances are provided between them to permit air from the duct 11 to enter and cool the bearing internally, a small outlet (not shown) being provided to permit such air to leak away after it has cooled the hearing. it will be seen therefore that the nozzle bearing is insulated from the hot jet pipe by the air duct 11 through which passes the relatively cold by-pass air and further that some of this cold air is tapped to cool internally the bearing parts. The by-pass air also cools the jet pipe and the nozzle.

The downstream end portion of the wall of the jet pipe 2, is formed with an inward lip such that the end overlaps the upstream end portion of the inner wall 14 of the nozzle on the inside, leaving a radial gap between them. The end of the inner wall 1 3- is correspondingly ".ssage is formed cation with the air communication with chamfered so that a sloping annular p having its upstream end in commt duct and its downstream end in the gas passage. If the pressure of the air is sufficiently high in relation to that of the gas in the region of the overlap, air can pass through the sloping passage with a rearward component of velocity which, enables it to form a coolant layer on the internal surface of the wall 14 of the nozzle.

The single oifset nozzle 13 for the whole of the engine gas and air discharge is rotated by any suitable means (not shown) so that it may turn through approximately 186 to the position outlined in chain dotted lines in FEGURE 2 which is the position for full braking thrust. When the nozzle is directed downwards, the discharge therefrom will give an upthrust. T he invention is therefore especially useful in connection with V.T.O.L. or S.T.O.L. aircraft in which the engine provides both lifting thrust for take-off and landing and forward thrust for forward propulsion. 1

A horizontal swinging tie-link 35 (see FTGURE 1) connecting the nozzle 13 to suitable supporting structure may be employed to carry a portion of the nozzle loading during forward propulsion.

Referring now to the construction shown in FIGURES 4 to 6, the parts corresponding to those in FIGURES l to 3 are indicated by the same reference numerals. This construction differs principally in that the nozzle has no inner wall to form a continuation of the wall of the st pipe 12, and the gas and air streams are therefore not separated in the nozzle. The nozzle has a similar bearingarrangement to that shown in FTGURE 3.

In this construction the jet pipe 12 and annular air duct 11 are formed and disposed to deflect the gas and air streams downwardly and laterally. As shown in FIGURE 6, the jet pipe Hand air duct 11 are formed to deflect the gas and air through 45, and are mounted on the engine in the angular position shown in FIGURE 5 to direct the air and gas laterally at an angle of 45 below the horizontal plane. The nozzle deflects the gas and air stream through 40, and when in the position shown in the drawings directs the stream at an angle of 5 away from the axis of the engine as seen in FIGURE 6 in order to keep the stream away from the adjacent part of the nacelle or fuselage of the aircraft and with a downward inclination of 3 as seen in FIGURE 4. Rotation of the nozzle anticlockwise through 160 from the position shown in FIGURE 5 brings it into a position for an assisted take-off in which position the discharge is directed downward parallel to a vertical plane containing the lengthwise axis of the engine but at a rearward inclination of about'27 to the vertical. A further anticloclrwiserotation of 30 brings the nozzle into a position for vertical take-off in which position the discharge is directed at an angle of'about .15 away from the vertical plane containing the lengthwise axis of the engine and with a rearward inclination of about 15 to the vertical. 7

The above arrangement has the advantages over that of FIGURES 1 to 3 that the frontal area of the engine is reduced and that the energy losses in the system are less due to the lesser angles of deflection of the gas and air in the jet pipe and nozzle.

one arrangement in which the engines are installed in an aircraft, gas turbine jet propulsion engines of the ducted fan type or by-pass type and substantially as described above are employed and are paired to provide a symmetrical thrust, each engine having its double flow propulsion nozzle projecting to one side being paired with an engine having its propulsion nozzle projecting to the opposite side. For example, in an aircraft having jet engines carried in pods mounted from the wings, each pod contains two engines arranged side by side with their rewective propulsion nozzle projecting laterally away from each other. In such arrangements, the nozzles of the engines of each pair will be rotated simultaneously in opposite directions.

The invention has application not only in constructions incorporating a rotatable propulsion nozzle of elbow-pipe form but may be applied to a nozzle which is substantially straight and which is rotatable about an axis oblique to the lengthwise of its inlet portion for control of the direction of discharge.

1 claim:

l. A gas turbine jet propulsion engine having first and second compressors, a combustor connected to be supplied with air from the compressors, a turbine system coupled to drive the compressors, a jet pipe connected to receive exhaust gases from the turbine system, an air duct connected to receive by-pass air from the first compressor, first compressor being arranged to supply a substantial proportion of its discharge into said air duct and another substantial proportion of its discharge ,into the second co: pressor, and a propulsion nozzle which is connected to receive exhaust gas from the jet pipe and air from the lay-pass air duct for discharge to atmosphere as a propulsive jet, and which is rotatable relative to the engine, rotation of the nozzle serving to adjust the direction of its discharge of the gas and air through at least substantially 90 while maintaining the area of the outlet for the propulsive jet constant.

2. A gas-turbine engine as claimed in claim 1, wherein the propulsion nozzle has coaxial inner and outer Walls defining an inner passage and an annular outer passage, the inner passage receiving the gas and the annular outer passage receiving the compressed air.

3. A gas turbine jet propulsion engine having a longitudinal axis and including first and second compressors, a cornbustor, and a turbine system arranged to drive the compressors, a single propulsion nozzle, gas ducting which extends from the discharge end of the turbine system to the inlet end of the nozzle, a by-pass air duct which extends from the discharge end of the first compressor to the inlet end of the nozzle, the discharge lrom the firs compressor being divided so that one substantial portion thereof is supplied to the by-pass duct and another substantial portion thereof is supplied to the second compressor, and means for rotating the nozzle to vary the direction of its discharge of by-pass air and exhaust gas, the gas ducting bein of elbow-form which is shaped to turn the exhaust gas flow through substantially 90, and nozzle being rotatable to vary the. direction of its luv discharge between 90 and 180 in a plane which is substantially parallel to the engine axis.

4. An engine according to claim 3, in which the nozzle is shaped to form an elbow-pipe extension of the by-pass duct and has an oblique outlet plane which at the inner bend of the nozzle lies close to the nozzle bearing.

5. A gas turbine jet engine including a compressor, a combustor and a turbine driving the compressor, a jet pipe terminating in a propulsion nozzle which receives the turbine exhaust gas, and a by-pass air duct which extends from the discharge end of the compressor to the nozzle, the compressor being arranged to supply a substantial portion of its air discharge to the by-pass duct and another portion of its air discharge for burning in the combustor, the nozzle being rotatable relative to the engine to vary the direction of its discharge of the bypass air and jet pipe gas through at least substantially 90, and the jet pipe and by-pass duct each including a downstream section which bends away from the axis of the turbine so that the nozzle is offset from the turbine axis.

References Cited by the Examiner UNITED STATES PATENTS 3 5 3 Nordfors 6035 .6 1/55 Goebel. 11/55 Lombard.

3/59 Smith et a1. 8/59 Philpot 60-35.6 11/59 Singlemann et al.

4/60 Britt 60-3555 3/62 Moorehead 60-35.55 7/62 Thomas et al 60-3555 FOREIGN PATENTS 8/56 Great Britain.

OTHER REFERENCES German application (1,070,448) Dec. 3, 1959.

SAMUEL LEVINE, Primary Examiner. 

1. A GAS TURBINE JET PROPULSION ENGINE HAVING FIRST AND SECOND COMPRESSORS, A COMBUSTOR CONNECTED TO BE SUPPLIED WITH AIR FROM THE COMPRESSORS, A TURBINE SYSTEM COUPLED TO DRIVE THE COMPRESSORS, A JET PIPE CONNECTED TO RECEIVE EXHAUST GASES FROM THE TURBINE SYSTEM, AN AIR DUCT CONNECTED TO RECEIVE BY-PASS AIR FROM THE FIRST COMPRESSOR, THE FIRST COMPRESSOR BEING ARRANGED TO SUPPLY A SUBSTANTIAL PROPORTION OF ITS DISCHARGE INTO SAID AIR DUCT AND ANOTHER SUBSTANTIAL PROPORTION OF ITS DISCHARGE INTO THE SECOND COMPRESSOR, AND A PROPULSION NOZZLE WHICH IS CONNECTED TO RECEIVE EXHAUST GAS FROM THE JET PIPE AND AIR FROM THE BY-PASS AIR DUCT FOR DISCHARGE TO ATMOSPHERE AS A PROPULSIVE JET, AND WHICH IS ROTATABLE RELATIVE TO THE ENGINE, ROTATION OF THE NOZZLE SERVING TO ADJUST THE DIRECTION OF ITS DISCHARGE OF THE GAS AND AIR THROUGH AT LEAST SUBSTANTIALLY 90* WHILE MAINTAINING THE AREA OF THE OUTLET FOR THE PROPULSIVE JET CONSTANT. 